Overhead conveyor installation

ABSTRACT

An electrically powered overhead conveyor system for a series of suspended load-carrying carts consists of a number of drive assemblies to suspend the carts in rolling engagement with a hollow rail having a cross-section resembling an inverted U which encloses the drive assemblies, and at least one drive assembly for each cart includes a driving motor which is entirely contained within the hollow rail.

United States Patent 1 1 Hermann 14 1 Apr. 2, 1974 OVERHEAD CONVEYORINSTALLATION [76] Inventor: Horst M. Hermann, Ulmenstr. 18,

7034 Maichingen, Germany [22] Filed: Apr. 19, 1972 [21] Appl. N0.:245,320

[52] US. Cl 104/94, 104/152, 295/1 [51] Int. Cl B6lb 3/02 [58] Field ofSearch.. l04/39, 93, 148, 94, 148 LM,

[56] References Cited UNITED STATES PATENTS 8/1965 Chadenson 104/9410/1962 Chadenson 104 94 11/1958 Eldridge, Jr. 104 149 2/1969 Klamp104/94 5/1966 Atanasoff et al. 105/150 Primary Examiner-Robert J. SparAssistant ExaminerRichard A. Bertsch [57] ABSTRACT An electricallypowered overhead conveyor system for a series of suspended load-carryingcarts consists of a number of drive assemblies to suspend the carts inrolling engagement with a hollow rail having a crosssection resemblingan inverted U which encloses the drive assemblies, and at least onedrive assembly for each cart includes a driving motor which is entirelycontained within the hollow rail.

8 Claims, 3 Drawing Figures @MENIEUAPR 21914 3 800 707 sum 2 or 2OVERHEAD CONVEYOR INSTALLATION the ceiling or from supports and ofconveyor cartsdriven and guided on said rails by means of individualwheel drive assemblies.

Known overhead conveyor installations of this type are intended mostlyfor industrial plants where trained personnel operate the installation.Accordingly, it can be assumed that this personnel treat the dangerousparts of these installations, such as the driving motors, the wheels andother rotating parts, as well as power inlets, with the required care.Such precautions based on familiarity with operational hazards can notbe expected when overhead conveyor installations are operated byuntrained personnel or laymen, as is the case, outside of commercialoperations, especially in hospitals or for example, for the conveyanceof luggage by passengers in the case of airports. In this case, theknown installations are too unsafe and thus dangerous.

The inventionhas' for its initial object the provision of an overheadconveyor installation with a high safety factor which makes it foolproofas far as laymen are concerned and which is suitable for example, forhospitals, airports, railway stations, etc.

This object according to the invention is achieved by the fact that aseparate motor is connected to every cart and that the rails are formedin the shape of hollow sections in such a way that they encompass themotors as well as their drive assemblies. In the case of a preferredembodiment of the invention, the live currentcarrying rails also aredisposed inside the hollow section of the rails and, of course,advantageously on the horizontal ceiling of the section. In this case,all the dangerous parts of the installation are covered up by the hollowsections of the rail in such a way that they normally are inaccessibleand, therefore, are not dangerous to anyone.

Special advantages will result in the operation of the overhead conveyorinstallation according to the invention, by employing three-phaseinduction motors, each of which can be operated according to choice atvarious specific frequencies so that in this manner different controlfunctions can be carried out.

Whenever the motor, as provided according to the invention, is to behoused inside the hollow section of the rails, it is important todistribute the driving force evenly, so that as small as possible amotor can be used. Therefore, according to another embodiment of theinvention, provision is made for thhe purpose of an even distribution ofthe wheel load, and thus of the driving force, that the drive assembliesare connected swivelably with the conveyor carts in a plane that isperpendicular to the direction of movement and that the swiveling axisis essentially at the same height as the running surface of the rails.

It furthermore will result in improvement of the drivin g and runningcharacteristics of the conveyor installation according to the invention,whenever the rims of the wheels disposed on the drive assembly are madeof a material, such as rubber, etc., which is noiseless when running andif the rims of the wheels are provided with guide beads made of asynthetic material with a low friction coefficient, such as polyamide,by means of which the wheels are guided slidingly by the inside of thehollow rail sections. At the same time, the hollow rails, at least inthe area of the guide beads, can be lined with a similar syntheticsubstance. It furthermore is of advantage to form the rim integrallywith the guide beads.

The subsequent description of preferred embodiments of the inventionserves in connection with the attached drawing for further explanationof the invention.

FIG. 1 shows a side view partially broken away of an overhead conveyorinstallation according to the invention;

FIG. 2 shows a front view of the overhead conveyor installation of FIG.1, on an enlarged scale as compared to FIG. 1;

FIG. 3 is a cross-section along line 33 in FIG. 1.

The overhead conveyor installation according to the invention,'conprises a plurality of hollow sectioned rails 1 having an essentiallyinverted U-shaped cross section, whereby the rails are open at thebottom and the perpendicularly downwardly directed sides termimate in apair of horizontally inwardly directed flanges which constitute therunning surfaces 2 for the wheels 3 of a drive assembly 4. Rails 1 maybe suspended from shackles 6 by means of stirrups 5 of a suitable shapewhich encases rail 1 from the outside and especially supports therunning surfaces 2. Shackles 6 on their part can be suspended eitherfrom the ceiling of a room or from special supports.

Inside the hollow sectioned rails 1, electrical conduc-' tor rails 8 aredisposed on the horizontal ceiling 7, the

- number of said rails depending on the type of power used, which in thecase of use of a three-phase motor would be three. Rails 8 are separatedfrom the ceiling 7 of rail 1 by insulators 9.

Each of the drive assemblies 4 comprises a pair of straps 11 on each ofwhich two wheels 3 opposite each other are mounted by means of ballbearings 12. F urthermore, three upwardly directed sliding contacts 13are connected with a frame 11, shown in FIG. 2 and at the extreme leftin FIG. 1, which take the current from rails 8 and feed it by means ofsuitable wiring (not shown) to a driving motor 14. Motor 14 includes adrive mechanism connected with another pair of wheels with its drivemechanism encased by a common housing rigidly connected with a strap 11supporting said wheels, as seen in FIG. 1. Strap 11 provided with thecurrent collecting sliding contacts 13 and strap 11 carrying drivingmotor 14 are connected jointedly with one another into a first driveassembly 4. The connection of the two straps l 1 is accomplished in sucha way that two shackles 15 projecting downwards, are connected with eachstrap 11. Between these shackles 15, a bushing element 17 is mountedswivelably by means of a hinge bolt 16 (see FIG. 2). Pairs of bushingelements 17 are connected with one another by means of a connecting bar18. On bar 18, a loop 21 is suspended for rotation around aperpendicular axis 19 indicated in dotted lines in FIG. 2, byconventional support means, on which loop a suspending rod 23 isattached by means of shackles 22. This suspending rod constitutes a partof a conveyor cart, not shown, and connected with it. On the basis ofthe joint effect imparted by means of bolt 16, the conveyor cart isconnected swivelably with the drive assembly 4 in a plane perpendicularto the direction of movement, whereby the horizontal longitudinalswiveling axis defined by bolt 16 lies at the same level as the runningsurface 2 of the 'rails. As a result of that, a particularly evendistribution of the wheel load will be obtained as well as of thedriving force produced by motor 14, so that the output of the motor canbe kept relatively low.

As can be gathered from FIG. 1, the wheel assembly 4 lying on the leftside in this drawing consists of a right-hand and left-hand pair ofwheels. The left-hand pair of wheels is connected (compare FIG. 2) withthe sliding contacts 13, while the driving motor 14 with its drivemechanism is disposed on the right-hand pair of wheels. The drivemechanism of the motor is positively connected with at least one runningwheel 3 of the right-hand pair of wheels, said running wheel constituting the driving wheel. The pair of drive assemblies 4 lying on theleft-hand side in FIG. 1 are also connected with another pair of driveassemblies 4 lying on the right-hand, side via the suspension rod 23,whereby each of the pairs of drive assemblies 4 with respect to the rod23 are rotatable around the above mentioned vertical axis 19 (FIG. 2).Whenever rod 23 is connected with a conveying cart in this way, acompact and yet flexible unit will be obtained, which can moveespecially through curved sections of rail having small radii ofcurvature.

As can be seen from FIG. 1, the driving motor 14 with its gear mechanismis disposed entirely within hollow rail section-land isenclosed andcovered by this rail in such a way that it is practically inaccessiblefrom the outside. This covering of the driving motor together with thearrangement of live conductor rails 8 on ceiling 7 of rail 1 constitutesa safety factor of considerable value.

Motor 14 can be a three-phase induction motor which can be operatedaccording to choice at variable frequencies adjustable in stages orcontinuously. The

frequency range can extend, for example, from between 25 to 100 Hz andin the case of a preferred embodiment, it will comprise three stages,namely, 25, 50 and 100 Hz. In this manner, the motors 14 of variousconveying carts are individually controllable by means of correspondingselection of frequencies.

The suspension rod 23 connected with the conveyor cart includes at eachof its ends a spring operated bumper 24 having damping means telescopingin the bar. The maximum suspended load on rod 23 can amount, forexample, to 150 kg or more. In the case of this suspended load, aconveying speed of, for example, about 150 m/min can be achieved. Eachof the rail sections 1 can be about 4 to m. long. As an operatingvoltage, a three-phase current of, for example, 3 X 42 V is preferredwith a view to the safety that is to be provided, whereby the drivingmotor has a rated capacity of about 150 Watts. A- safety switch 25operated by the spring bumpers 24 is disposed on the suspension rod 23,which upon running into an obstacle or into the bumper of anotherconveyor cart, will switch off driving motor 14.

In FIG. 2, a three-phase voltage source is schematically indicated bynumeral 50, the frequency of which is continuously adjustable, by meansof a control lever 51, between 25 Hz. and 100112. The voltage source 50is connected by wires 52 to the individual conductor rails 8. In thismanner it is possible to double the travel speed of a conveyor carriagealong a particular section of the track forming the conveyorinstallation by changing the frequency of the voltage source 50 fromabout 50 Hz. to 100 Hz. A reduction of the frequency in a certainsection of the track will result, along that section, to a correspondingdecrease in the travel speed.

According to a further development of the invention as shown in FIG. 3,the wheels 3 disposed on the drive assemblies 4 have wheel rims 26 madeof a silently and elastically running raw material, such as rubber, etc.The lower sections 27 of the two sides of the hollow rail 1 each runslantingly inwardly and they cooperate with an annular guide bead 28provided concentrically with reference to the axle of the wheel 3 withthe aid of which bead the wheels are guided slidingly along the insideof the hollow rails 1 preferably lined likewise with some syntheticsubstance. Guide bead 28 is connected with rim 29 of wheel 3 .or it canbe made with said rim in one piece. Bead 28 may consist of a syntheticsubstance with a low friction coefficient, such as polyamide.

The conveyor carts of the overhead installation according to theinvention, easily can overcome a gradient of up to 4 percent with a loadof about kg and a speed of about 150 m/min. For higher gradients up to36 percent, an auxiliary drive motor can be provided on the driveassembly which likewise is completely covered up by the hollow railsections.

I claim:

1. Overhead conveyor installation for transporting a plurality ofindividual carts, comprising a series of hollow rail sections having agenerally inverted U-shaped cross-section to be suspended from overheadsupports, and a plurality of drive assemblies including means to suspenda cart therefrom, each of said drive assemblies being confined withinsaid hollow rail sections in loadbearing rolling engagement with theinterior thereof, said drive assemblies including a pair ofloadsupporting wheels for rolling engagement with respective oppositelower interior surfaces of the hollow rail sections, the rollingsurfaces of said wheels comprising a silently running composition, saidwheels also including an annular bead comprising a material of lowcoefficient of friction for guiding contact with the respective innersides of the hollow rail sections, at least one drive assembly for eachcart including electric motor drive means completely enclosed withinsaid hollow rail sections to propel said one assembly, and means tosupply electrical energy to each of said electric motor drive means froma source of electricity.

2. The invention defined in claim 1, wherein said means to supplyelectrical energy includes an electrically conductive rail extendingalong the interior of, and enclosed by, said hollow rail sections.

3. The invention defined in claim 2, wherein said electricallyconductive rail is disposed at the uppermost portion of the hollow railsections.

4. The invention defined in claim 1, wherein the electric motor drivemeans includes a three-phase motor capable of operation from electricalenergy supplied at a plurality of different frequencies.

5. The invention defined in claim 4, wherein said means to supplyelectrical energy includes common conductor means to supply three-phaseelectrical power at a plurality of frequencies to a plurality ofelectric motor drive means, each of said electric motor drive meansbeing connected with only a single cart, each of said electric motormeans being operably responsive to only one of said plurality offrequencies.

6 6. The invention defined in claim 1, wherein said 7. The inventiondefined in claim 1, wherein said mameans to suspend a cart includes twopivotally conterial of low coefficient of friction includes polyamide.nected elements, one of said two elements being sup- 8. The inventiondefined in claim 1, wherein the rollported by said pair of wheels toposition the axis of said ing surfaces and the annular bead of saidwheels is intepivotal connection at right angles to the axis of said 5grally formed of a silently running composition having wheels and inalignment with the horizontal plane of a low coefficient of friction.

said lower interior surfaces.

1. Overhead conveyor installation for transporting a plurality ofindividual carts, comprising a series of hollow rail sections having agenerally inverted U-shaped cross-section to be suspended from overheadsupports, and a plurality of drive assemblies including means to suspenda cart therefrom, each of said drive assemblies being confined withinsaid hollow rail sections in load-bearing rolling engagement with theinterior thereof, said drive assemblies including a pair ofloadsupporting wheels for rolling engagement with respective oppositelower interior surfaces of the hollow rail sections, the rollingsurfaces of said wheels comprising a silently running composition, saidwheels also including an annular bead comprising a material of lowcoefficient of friction for guiding contact with the respective innersides of the hollow rail sections, at least one drive assembly for eachcart including electric motor drive means completely enclosed withinsaid hollow rail sections to propel said one assembly, and means tosupply electrical energy to each of said electric motor drive means froma source of electricity.
 2. The invention defined in claim 1, whereinsaid means to supply electrical energy includes an electricallyconductive rail extending along the interior of, and enclosed by, saidhollow rail sections.
 3. The invention defined in claim 2, wherein saidelectrically conductive rail is disposed at the uppermost portion of thehollow rail sections.
 4. The invention defined in claim 1, wherein theelectric motor drive means includes a three-phase motor capable ofoperation from electrical energy supplied at a plurality of differentfrequencies.
 5. The invention defined in claim 4, wherein said means tosupply electrical energy includes common conductor means to supplythree-phase electrical power at a plurality of frequencies to aplurality of electric motor drive means, each of said electric motordrive means being connected with only a single cart, each of saidelectric motor means being operably responsive to only one of saidplurality of frequencies.
 6. The invention defined in claim 1, whereinsaid means to suspend a cart includes two pivotally connected elements,one of said two elements being supported by said pair of wheels toposition the axis of said pivotal connection at right angles to the axisof said wheels and in alignment with the horizontal plane of said lowerinterior surfaces.
 7. The invention defined in claim 1, wherein saidmaterial of low coefficient of friction includes polyamide.
 8. Theinvention defined in claim 1, wherein the rolling surfaces and theannular bead of said wheels is integrally formed of a silently runningcomposition having a low coefficient of friction.